RING-BACKUP 5J7865 - Caterpillar

Introduction
This troubleshooting guide can be an aid for the service personnel to find the cause of existing problems. Several common problems are covered in the guide, but these problems are not arranged in any particular sequence.Identify your particular type of problem from the Troubleshooting Index, then go directly to that problem in the guide. However, when you begin the procedure for that problem, start at Step 1 and follow through the step by step procedure. The steps that follow in a particular problem provide a definite sequence to be followed for a logical, one by one elimination of many variables. These steps are arranged in order from the more probable/easiest to check, to the less probable/more complex to check.Whenever the cause of the problem is found and corrected, stop the test. Do not continue through the complete procedure just because it is there.Governor Only
Problem No. 1: Governor Does Not Open On Starting
Probable Cause:1. No signal from magnetic pickup. Verify with AC voltmeter or Oscilloscope.Excessive pickup clearance. Adjust clearance to 0.5 to 0.8 mm (.02 to .03 in) if necessary.Check resistance at cable socket of governor control unit A2/B2 (approx. 200 ohms). Replace cable or speed pickup if needed.Check starting speed voltage at cable socket of governor control unit A2/B2 (approx. 5V AC). Replace or clean speed pickup if needed. The governor must have its own speed pickup. It cannot share a pickup with another device.Wiring fault - magnetic pickup defective. Repair or replace as needed.Control lamp must be lit when power supply is on and must go out from starting frequency upwards. If the governor works with the governor test unit but not on the engine, the fault is in the speed pickup or speed pickup cable.2. Shutdown switch on.Disconnect shutdown at pins H3 & I3 for troubleshooting.3. Set point potentiometer connections wrong or incomplete.Disconnect 14 pin connector from governor control unit and use ohmmeter to verify the resistance at the cable socket of the wiring harness.Remote speed set point potentiometer at minimum speed: Remote speed set point potentiometer at maximum speed: 4. Set point potentiometer or maximum speed/low speed potentiometer settings too low.Verify speeds are correct with governor test unit.5. Wiring fault in cable harness.6. Supply voltage inadequate or polarity reversed.Verify with DC voltmeter.7. No DC voltage at governor control unit.Verify with DC voltmeter.8. Actuator impeded or linkage adjusted wrong.Manually move linkage to verify.9. Start fuel limit incorrectly adjusted (if used).Put start fuel limit switch in position 2 or 3. Try to start engine. If engine starts, shut down engine, put start fuel limit slide switch in position 4. Re-adjust start fuel limit according to "Start Fuel Limit Adjustment" procedure in the Initial Checks & Adjustments section.10. Open or shorted speed pickup cable or speed set point cable.Verify with ohmmeter.11. Actuator defective.Check resistance at terminals B-C on actuator (approx. 2 ohms).Replace actuator.12. Governor control unit defective.Replace governor control unit.Problem No. 2: Governor Moves To Maximum Fuel Injection When Power Supply Is On
Probable Cause:1. Wiring fault in harness.2.